|Subject to the provisions of sub-regulation
(e) of regulation 381, every boiler shall be hydraulically
tested after erection at site in presence of the
Inspector to 1¼ times the maximum working
pressure as certified by the Inspecting Authority
in Form II, to be stamped on the boiler, as free
from any indication of weakness or defects.
||If all components of the boiler in
the manufacturers premises have not been tested
hydraulically as per regulation
268, the test, on
completion, shall be taken to 1½ times the
maximum working pressure.
||The temperature of the water used
as medium of pressure testing shall not be less
than 20°C and greater than 50°C.
||The test pressure shall be raised
gradually under proper control at all times so that
it never exceeds by more than 6% of the required
pressure and maintained for 30 minutes whereupon
the pressure shall be reduced to maximum allowable
working pressure and maintained for sufficient time
to permit close visual inspection for leakage of
||The boiler shall satisfactorily withstand
such pressure without appreciable leakage or undue deflection
or distortion of its parts for at least ten consecutive
minutes. If the test is not satisfactory, the working
pressure allowable by calculation shall be suitably reduced,
unless the owner desires to make such alterations as will
enable the boiler to withstand satisfactorily the hydraulic
test, in which case the boiler shall again be examined
after the alterations have been made, the pressure recalculated,
if necessary, and the boiler tested to the satisfaction
of the Inspector.
||* At the first hydraulic test of
a boiler prior to the issue of an original certificate
deflection measurements shall be made before, during and
after test of each furnace length, fire-box and flat end
or other plates.
||After the application of the hydraulic
test the Inspector shall carefully examine the boiler
inside and outside and satisfy himself that it has satisfactorily
withstood the test.
||In any case in which the safe working pressure
to be allowed for a boiler cannot, owing to peculiar construction
of any of its parts, be determined by calculation in the
ordinary way, the Inspector shall, under the direction
of the Chief Inspector, subject the boiler to hydraulic
test for the purpose of determining the fitness of such
parts. The amount of the test pressure to be applied in
such a case shall not exceed the test pressure prescribed
for the least working pressure found by calculation for
other parts of the boiler or the intended working pressure
whichever is less.
||Should any part of the boiler show undue
deflection or indication of permanent set during the progress
of the test, the pressure shall be released immediately
such indications are observed. The working pressure for
the part shall be 40 per cent of the test pressure applied
when the point of permanent set was reached. This procedure
shall apply to any boiler at any test.
||Hydraulic tests of boilers at subsequent
examination shall, except when the Inspector expressly
requires otherwise, be made after the inspection. The
test pressure to be applied to boilers at such subsequent
examinations shall be from one and a quarter to one and
a half times the working pressure of the boiler.
||When the internal construction of size
of a boiler does not permit of the Inspector getting inside
it or of examining closely all its parts, he shall see
it tested by hydraulic pressure to one and a half times
the working pressure at each inspection or the grant or
renewal of a certificate.
||Water tube locomotive type and all tubular
boilers shall be hydraulically tested at each inspection
for the grant or renewal of a certificate, unless such
test is waived under the order of the Chief Inspector.
||The Inspector may if the considers it necessary,
apply a hydraulic test to any boiler at any inspection.
||Except in the case of vertical boilers,
heating surface of which is less than 18.58 sq.m. (200
sq. ft.), portable and vehicular boilers, which do not
require re-erection or building in brickwork, the hydraulic
test of all boiler shall be conducted only after the erection
of the boiler in situ and all boilers shall after re-erection
in a position different from that in which they were last
examined be hydraulically tested.
|* NOTE:-These deflection
measurements should be entered in the Memorandum of Inspection
Book before its submission to the Chief Inspector.
||A hydraulic test shall also be taken before
granting an increased pressure certificate and after repairing
a boiler. However, in the case of minor repairs to the
Water Tube boilers where NDT has been carried out, hydraulic
testing may be dispensed with provided NDT is carried
out by an approved method.
||When carrying out hydraulic test, Inspectors
shall use pressure gauges supplied by the Chief Inspector.